Tiny210触摸屏之一线触摸屏驱动-EDA365

单片机 > 单片机程序设计 > 详情

Tiny210触摸屏之一线触摸屏驱动

发布时间：

1wire_ts.c源码：

#include "linux/errno.h"

#include "linux/kernel.h"

#include "linux/module.h"

#include "linux/slab.h"

#include "linux/input.h"

#include "linux/init.h"

#include "linux/serio.h"

#include "linux/delay.h"

#include "linux/clk.h"

#include "linux/miscdevice.h"

#include "linux/platform_device.h"

#include "linux/timer.h"

#include "linux/param.h"

#include "linux/poll.h"

#include "linux/proc_fs.h"

#include "linux/gpio.h"

#include "linux/cdev.h"

#include "linux/sched.h"

#include "linux/interrupt.h"

#include "linux/irq.h"

#include "linux/err.h"

#include "linux/io.h"

#include "asm/system.h"

#include "asm/leds.h"

#include "asm/mach-types.h"

#include "asm/irq.h"

#include "asm/mach/time.h"

#include "asm/io.h"

#include "asm/irq.h"

#include "asm/uaccess.h"

#include "mach/map.h"

#include "mach/regs-irq.h"

#include "mach/regs-clock.h"

#include "mach/regs-gpio.h"

#include "plat/regs-timer.h"

#include "plat/gpio-cfg.h"

#include "plat/clock.h"

#include "plat/cpu.h"

static DECLARE_WAIT_QUEUE_HEAD(ts_waitq);

#define MHZ (1000*1000)

#define PRINT_MHZ(m) ((m) / MHZ), ((m / 1000) % 1000)

#define TOUCH_DEVICE_NAME "tiny_ts"

#define SAMPLE_BPS 9600

#define SLOW_LOOP_FEQ 25

#define FAST_LOOP_FEQ 60

#define REQ_TS 0x40U

#define REQ_INFO 0x60U

enum {

IDLE,

START,

REQUEST,

WAITING,

RESPONSE,

STOPING,

} one_wire_status = IDLE;

struct timer_regs {

unsigned long tcfg0;

unsigned long tcfg1;

unsigned long tcon;

unsigned long reserved1[9];

unsigned long tcntb3;

unsigned long tcmpb3;

unsigned long tcnto3;

unsigned long reserved2[2];

unsigned long tint_cstat;

};

static struct timer_regs *timer_regs;

static unsigned long *gph1con;

static unsigned long *gph1dat;

static int ts_ready;

static unsigned ts_status;

static unsigned lcd_type, firmware_ver;

static unsigned total_received, total_error;

static unsigned last_req, last_res;

static unsigned long TCNT_FOR_SAMPLE_BIT;

static volatile unsigned int io_bit_count;

static volatile unsigned int io_data;

static volatile unsigned char one_wire_request;

static int exitting;

static struct timer_list ts_timer;

static inline void notify_ts_data(unsigned x, unsigned y, unsigned down)

{

if (!down && !(ts_status &(1U << 31))) {

// up repeat, give it up

return;

}

ts_status = ((x << 16) | (y)) | (down << 31);

ts_ready = 1;

wake_up_interruptible(&ts_waitq);

}

static ssize_t ts_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)

{

unsigned long err;

if (!ts_ready) {

if (filp->f_flags & O_NONBLOCK)

return -EAGAIN;

else

wait_event_interruptible(ts_waitq, ts_ready);

}

ts_ready = 0;

if (count < sizeof ts_status) {

return -EINVAL;

} else {

count = sizeof ts_status;

}

err = copy_to_user((void *)buffer, (const void *)(&ts_status), sizeof ts_status);

return err ? -EFAULT : sizeof ts_status;

}

static unsigned int ts_poll( struct file *file, struct poll_table_struct *wait)

{

unsigned int mask = 0;

poll_wait(file, &ts_waitq, wait);

if (ts_ready)

mask |= POLLIN | POLLRDNORM;

return mask;

}

static struct file_operations ts_fops = {

owner: THIS_MODULE,

read: ts_read,

poll: ts_poll,

};

static struct miscdevice ts_misc = {

.minor = 181,

.name = TOUCH_DEVICE_NAME,

.fops = &ts_fops,

};

static inline void notify_info_data(unsigned char _lcd_type,unsigned char ver_year,

unsigned char week)

{

if (_lcd_type != 0xFF) {

lcd_type = _lcd_type;

firmware_ver = ver_year * 100 + week;

}

static inline void set_pin_value(int v)

{

if (v) {

*gph1dat |= 1<<2;

} else {

*gph1dat &= ~(1<<2);

}

static inline int get_pin_value(void)

{

if(*gph1dat & (1<<2))

return 1;

else

return 0;

}

// CRC

static const unsigned char crc8_tab[] = {

0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,

0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,

0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,

0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,

0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,

0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,

0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,

0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,

0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,

0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,

0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,

0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,

0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,

0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,

0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,

0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,

0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,

0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,

0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,

0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,

0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,

0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,

0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,

0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,

0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,

0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,

0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,

0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,

0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,

0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,

0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,

0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3,

};

#define crc8_init(crc) ((crc) = 0XACU)

#define crc8(crc, v) ( (crc) = crc8_tab[(crc) ^(v)])

// once a session complete

static void one_wire_session_complete(unsigned char req, unsigned int res)

{

unsigned char crc;

const unsigned char *p = (const unsigned char*)&res;

total_received ++;

last_res = res;

crc8_init(crc);

crc8(crc, p[3]);

crc8(crc, p[2]);

crc8(crc, p[1]);

if (crc != p[0]) {

// CRC dismatch

if (total_received > 100) {

total_error++;

}

return;

}

switch(req) {

case REQ_TS:

{

unsigned short x,y;

unsigned pressed;

x = ((p[3] >> 4U) << 8U) + p[2];

y = ((p[3] & 0xFU) << 8U) + p[1];

pressed = (x != 0xFFFU) && (y != 0xFFFU);

notify_ts_data(x, y, pressed);

}

break;

case REQ_INFO:

notify_info_data(p[3], p[2], p[1]);

break;

default:

break;

}

// one-wire protocol core

static int init_timer3_for_ts(void)

{

struct clk *clk;

unsigned long pclk;

unsigned long prescaler;

unsigned long prescale1_value;

// 获得时钟，并使能时钟

clk = clk_get(NULL, "timers");

if (IS_ERR(clk)) {

printk("ERROR to get PCLK ");

return -EIO;

}

clk_enable(clk);

pclk = clk_get_rate(clk);

printk("Timer3 clock source : %ld.ld Mhz ", PRINT_MHZ(pclk));

// 获得定时器的预定标器的值,目的是为了不修改该值，因为定时器2，3，4共享它

prescaler = timer_regs->tcfg0;

prescale1_value = (prescaler >> 8) & 0xFF;

// calc the TCNT_FOR_SAMPLE_BIT, that is one of the goal

TCNT_FOR_SAMPLE_BIT = pclk / (prescale1_value + 1) / SAMPLE_BPS - 1;

// 定时器3的分频系数为1

timer_regs->tcfg1 &= (0xf<<12);

printk("TCNT_FOR_SAMPLE_BIT = %d ", TCNT_FOR_SAMPLE_BIT);

return 0;

}

static inline void stop_timer_for_1wire(void)

{

timer_regs->tcon &= ~(1<<16); // 停止定时器3

}

static irqreturn_t timer_for_1wire_interrupt(int irq, void *dev_id)

{

timer_regs->tint_cstat |= 0x100; // 清中断

io_bit_count--;

switch(one_wire_status)

{

case START:

if (io_bit_count == 0) {

io_bit_count = 16;

one_wire_status = REQUEST;

}

break;

case REQUEST:

// Send a bit

set_pin_value(io_data & (1U << 31));

io_data <<= 1;

if (io_bit_count == 0) {

io_bit_count = 2;

one_wire_status = WAITING;

}

break;

case WAITING:

if (io_bit_count == 0) {

io_bit_count = 32;

one_wire_status = RESPONSE;

}

if (io_bit_count == 1) {

*gph1con &= ~(1<<8);// 设置为输入

set_pin_value(1);

}

break;

case RESPONSE:

// Get a bit

io_data = (io_data << 1) | get_pin_value();

if (io_bit_count == 0) {

io_bit_count = 2;

one_wire_status = STOPING;

set_pin_value(1);

*gph1con |= 1<<8;// 设置为输出

one_wire_session_complete(one_wire_request, io_data);

}

break;

case STOPING:

if (io_bit_count == 0) {

one_wire_status = IDLE;

stop_timer_for_1wire();

}

break;

default:

stop_timer_for_1wire();

}

return IRQ_HANDLED;

}

static struct irqaction timer_for_1wire_irq = {

.name = "1-wire Timer Tick",

.flags = IRQF_DISABLED | IRQF_IRQPOLL,

.handler = timer_for_1wire_interrupt,

.dev_id = &timer_for_1wire_irq,

};

static void start_one_wire_session(unsigned char req)

{

unsigned long flags;

if (one_wire_status != IDLE) {

return;

}

one_wire_status = START;

set_pin_value(1);

*gph1con |= 1<<8; // 设置为输出

// IDLE to START

{

unsigned char crc;

crc8_init(crc);

crc8(crc, req);

io_data = (req << 8) + crc;

io_data <<= 16;

}

last_req = (io_data >> 16);

one_wire_request = req;

io_bit_count = 1;

*gph1con |= 1<<8; // 设置为输出

timer_regs->tcntb3 = TCNT_FOR_SAMPLE_BIT;

// 不手动装载，不电平反转，不自动装载

timer_regs->tcon &=~(0xF << 16);

timer_regs->tcon |= 1<<17; // 手动转载数据

local_irq_save(flags);

timer_regs->tcon |= 1<<16; // 开启定时器3，并开启自动装载

timer_regs->tcon |= 1<<19;

timer_regs->tcon &= ~(1<<17);// 关闭手动装载

set_pin_value(0);

local_irq_restore(flags);

}

void one_wire_timer_proc(unsigned long v)

{

unsigned char req;

if (exitting) {

return;

}

// 设置查询周期为20ms,并启动内核定时器

ts_timer.expires = jiffies + HZ / 50;

add_timer(&ts_timer);

if (lcd_type == 0) {

req = REQ_INFO;

}

else {

req = REQ_TS;

}

start_one_wire_session(req);

}

static int read_proc(char *buf, char **start, off_t offset, int count, int *eof, void *data)

{

int len;

len = sprintf(buf, "%u %u %u %u X X ",

lcd_type, firmware_ver, total_received, total_error, last_req, last_res);

*eof = 1;

return len;

}

static int dev_init(void)

{

int ret;

ret = misc_register(&ts_misc);

if (ret == 0) {

create_proc_read_entry("driver/one-wire-info", 0, NULL, read_proc, NULL);

printk (TOUCH_DEVICE_NAME" initialized ");

}

timer_regs = ioremap(0xE2500000, sizeof(struct timer_regs));

gph1con = ioremap(0xE0200C20, 8);

gph1dat = gph1con + 1;

// 设置GPH1_2为输出,并输出1

*gph1con |= 1<<8;

*gph1dat |= 1<<2;

setup_irq(IRQ_TIMER3, &timer_for_1wire_irq);

init_timer3_for_ts();

// 初始化内核的定时器

init_timer(&ts_timer);

ts_timer.function = one_wire_timer_proc;

one_wire_timer_proc(0);

// 使能定时器3中断，清中断

timer_regs->tint_cstat |= 0x108;

return ret;

}

static void dev_exit(void)

{

exitting = 1;

remove_proc_entry("driver/one-wire-info", NULL);

misc_deregister(&ts_misc);

del_timer_sync(&ts_timer);

free_irq(IRQ_TIMER3, &timer_for_1wire_irq);

iounmap(timer_regs);

iounmap(gph1con);

}

module_init(dev_init);

module_exit(dev_exit);

MODULE_LICENSE("GPL");

==============================================================

一线触摸屏介绍：

杂项设备：(由于在移植一线触摸屏驱动的时候，会用到杂项设备，下面分析下它的框架)

分析driverscharmisc.c的实现过程：

static const struct file_operations misc_fops = { //分配设置一个file_operations结构体

.owner = THIS_MODULE,

.open = misc_open,

};

static int __init misc_init(void) //入口函数

{

misc_class = class_create(THIS_MODULE, "misc"); //创建类

if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) //注册一个主设备号为10的字符设备

}

subsys_initcall(misc_init); //申明misc_init()函数到子系统初始化集

问：从上面的分析过程可以发现，该子系统初始化程序完全符号写一般的字符驱动程序的步骤，那么应用程序是怎么对通过misc_register()注册的设备进行相应的读，写等操作的呢？

答：过程如下：

app: open() 应用程序使用open函数

------------------------------------------------------------------------------------------------------------------

kernel:(内核最终会调用到misc.c中的file_operations结构体中的open函数)

问：当看上面的file_operations结构体的时候，发现里面只有一个open函数？那是怎么来实现一系列的其他的操作的呢（读，写...）?

答：可以猜测出，一定是在这个open函数里面做了一些设置，然后在新的设置里面来进行相关的操作。

static int misc_open(struct inode * inode, struct file * file)

{

int minor = iminor(inode); //获得次设备号

list_for_each_entry(c, &misc_list, list) { //从misc_list链表中取出每一项(即miscdevice结构体)

if (c->minor == minor) { //通过次设备号进行匹配

new_fops = fops_get(c->fops); //如果次设备号一样，则获得该项的file_operations结构体成员

}

if (!new_fops) { //如果上述操作，获得file_operations结构体没有成功，则再次获取

list_for_each_entry(c, &misc_list, list) {...}

}

file->f_op = new_fops; //重新初始化struct file结构中的成员f_op，让它指向新的file_operations！

if (file->f_op->open) { //如果新获得的file_operations结构体有open函数

err=file->f_op->open(inode,file); //则调用他的open函数

}

问：从分析以上open函数时，发现会从misc_list链表中取出某一项来获取一个miscdevice结构体，进而获取他的成员fops(即新的file_operations结构体),从而构建出了一个新的file_operations结构体，那么上述misc_list链表是由谁来设置的呢？即链表中的成员miscdevice结构体又由谁来传入呢？

答：收索最终发现，它在misc_register函数中被设置：

int misc_register(struct miscdevice * misc)

{

misc->this_device = device_create(misc_class, misc->parent, dev, misc, "%s", misc->name); //建设备节点

list_add(&misc->list, &misc_list); //将传入的参数miscdevice结构体放入misc_list链表

}

Tiny210的硬件原理：

问：Tiny210一线触摸屏到底是什么？

答：友善的人自以为傲的核心技术，设计了一个一线精准触摸电路，并集成到LCD 的驱动板上，它采用触摸屏控制芯片ADS7843(或者相类似)，配合一个ATC的单片机(该单片机里面固话了程序)，构成一个独立的四线电阻触摸屏采集电路，最后通过一个普通的GPIO口把处理过的数据发送出去，在开发板上与之相连的是GPH1_2，实现单总线通信，这就是一线的来源。

说白了，就是ATC单片机通过SPI和ADS7843通信，控制ADS7843去读写触摸屏的数据，然后将数据存在单片机里面的RAM中，然后再通过单片机的一个GPIO发给ARM。

问：能够自己写出一线触摸的驱动吗？

答：能使肯定的，但是有些烦躁：

(1).在开发板的原理图上面，与GPH1_2相连接的LCD管脚上面用的net为"PWM"，让人误以为是用PWM来通信(当然不可能，PWM是输出，无法读入数据)；

(2).上面说了，触摸屏的数据会经单片机处理后，然后通过一个IO管脚发个ARM，但是该IO发出的数据的格式是什么样子的呢(即时序，几秒代表1，几秒代表0)，由于友善把其视为核心技术，他们不向外提供固话在单片机中的程序(这个我能理解)，但是他们也不提供IO发出的数据的时序。但是大家可以去阅读他们提供的内核里面的触摸屏驱动，然后反推出时序是怎么样的。但是，我没有去弄了，我只是移植了。

最后说说，友善的一线触摸驱动是怎么写的，它在入口函数中注册了一个内核定时器，用于查询方式去读取IO上面的"一帧"数据，然后再启用一个定时器3去解码这些数据，具体怎么解码，请大家参考我移植好了的驱动，然后攻破它吧。写出文档，记得共享到群共享去，发扬互学互助的精神！！！

==============================================================

tslib编译使用_测试一线触摸屏：

tslib-one-wire.tar.bz2已经上传自同文件夹中，这是一个已经打过补丁，支持一线触摸屏测试的tslib

编译：

tar xjvf tslib-one-wire.tar.bz2

cd tslib-1.0.0

./autogen.sh

mkdir tmp

echo "ac_cv_func_malloc_0_nonnull=yes" >arm-linux.cache

./configure --host=arm-linux --cache-file=arm-linux.cache --prefix=$(pwd)/tmp

make